Thread-cutting die and holder



(N6 Model.) v

J. S. HEN-RY.

TH DDDDDDDDDDDD IE'AND HOLDER.

No. 374,599. V Patented Dec. 13; 1887.;

\lnlll UNITED STATES PATENT OFFICE.

' JOHN STEPHEN HENRY, OF STONINGTON, CONNECTICUT.

THREAD-CUTTING DIE AND HOLDER.

SPECIFICATION forming part of Letters Patent No. 374,599. dated December 13, 1887.

Application filed August 12, 1887. Serial No. 246.793. (No model.)

' pacity and permit ready removal and interchangcability.

In the accompanying drawings,forming part of this specification, Figure 1 is a perspective view of a device embodying my improvements. Fig. 2 is a transverse section of the same on the dotted line as w of Fig. 1. Fig. 3 is a detail view of the adjusting-screw and dies; Fig. 4, another detail view illustrating one of the die-plates from the rear. Fig. 5 is a detail view of a portion of the stock, the die-plate and screw being removed to show the form of recesses in said stock.

The stock or holder A is made in cy1indrical form, and is designed to be secured on any suitable mandrel or arbor by means of clamping devices, and is provided atits working end with a transverse recess of dovetail form. The face of the stock constituting the base of the recess is provided with a circular depression, which has centrally an offset, 1). A right-and-left-hand screw, B, is adapted to bear in said recess, and is provided centrally with a plain portion, on either side of which and extending toward the ends are the screwthreads e. The inner adjacent ends of the threaded portions bear against the sides of the offset and serve to prevent the screw from lateral displacement.

f and 9 refer to die-plates, which rest upon the bottom recess flush with the outer face of the stock, and each die is beveled and milled at its lower rear edge to engage the exposed portion of the screw. The dies f g are slightly less than the recess in which they move, leaving a narrow space between the projecting portion h of the stock and the sides of the dies, and in this space is inserted a gib or key, 15, which is adapted to be secured in position by means of set-screwsj, which pass through the portion h and bind the key. One end of the screw B is slotted to enable it to be turned in its bearing 'by any suitable tool. The rotation of the screw by reason of its right and left hand threads causes the die-plates to approach'or recede from each other, as the case may be, and thus increase or diminish the ca pacity of the cutter.

It will be obvious that the dovetail form of the recess and of the dies and key is such as to effectively guard against accidental displacement of the dies, and at the same time insure the proper engagement of said dies with the screw. Furthermore, by simply removing the key the dies can be withdrawn for replacement or recutting.

d I claim-+- The combination, ina thread-cutting die and holder, of the stock having the transverse dovetail recess, the transverse offset recess communicating with the dovetail recess and having the central shoulder, b, the dovetail cutting-dies f f in the dovetail recess, and the screw B, arranged in the offset recess, having an annular central groove engaging the shoulder 1) and having the right and left hand threads at opposite ends engaging threads in the adjacent edges of the cutting-dies, substantially as described.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in presence of two witnesses.

JOHN STEPHEN HENRY.

Witnesses:

' OTHO O. SULLIVAN,

GEO. L. DENISON. 

